1)The data management section of the core unit provides collection, storage and retrieval of data from all units of the center. 2) The statistical section of the core unit offers expertise to all investigators for analysis and interpretation of studies. The data management unit provides an extensive computer facility, with links to both the Presbyterian Hospital and the Columbia main campus computers. The unit downloads daily from the hospital computer all clinical and laboratory data relative to the patients and furnishes detailed summary to all patients' charts. An important goal of the statistical section of the core unit is to generate prognostic factors, from our own data on several hundred patients, by correlation of the genetic modifiers and hematological data with the clinical manifestations of the disease. The demonstration that a relatively low threshold of Hgb F concentration (greater than or equal to 4%) confers protection from stroke also suggests that drugs that may increase Hgb F concentration may result in prevention of this and other devastating complications of sickle cell diseases. A more complex and comprehensive picture will be generated to provide detailed prognostic factors that could be used to selectively program to specific patients that available therapies.